(1) Field of the Invention
The present invention relates to a display device where a transparent cover is pasted on the surface of a display panel using an adhesive.
(2) Related Art Statement
Liquid crystal display devices having a liquid crystal display panel, for example, are known as display devices. In many cases, a transparent cover, such as of an acryl resin, is provided on such a liquid crystal display panel on the viewer side (front side). This transparent cover works as a protective cover plate. However, the transparent cover is provided at a predetermined distance from the liquid crystal display panel, and therefore, there is an air layer between the transparent cover and the liquid crystal display panel. Therefore, there is unnecessary interface reflection, due to the difference in the index of refraction in the interface with the air layer, which is a factor affecting lowering of contrast in the display.
In order to solve this, a technology according to which a transparent cover is pasted on the surface of a liquid crystal display panel using an adhesive has been proposed. FIG. 11 is a cross sectional diagram showing the configuration of a conventional liquid crystal display device.
The liquid crystal display panel shown in FIG. 11 has a configuration where a first substrate SUB1 and a second substrate SUB2 are pasted together via a sealing material SL, and a liquid crystal layer LC is sandwiched between the first substrate SUB1 and the second substrate SUB2. In addition, a polarizing plate POL1 and a polarizing plate POL2 are provided on the first substrate SUB1 on the side opposite to the liquid crystal layer LC and on the second substrate SUB2 on the side opposite to the liquid crystal layer LC, respectively.
A transparent cover COV is pasted on the surface of the liquid crystal display panel on the viewer side using an adhesive ADH. The transparent cover COV is provided with a light blocking film BLK on the outside of the display region AR of the liquid crystal display panel. In addition, in the case where an adhesive ADH of which the index of refraction is close to that of the transparent cover COV is used, there is no air layer, and therefore, unnecessary reflection in the interface resulting from the index of refraction can be prevented, and the contrast in the display can be increased.
In addition to the conventional configuration shown in FIG. 11, prior art relating to the present invention are disclosed in the following Patent Documents 1 and 2, for example.    (Patent Document 1) Japanese Unexamined Patent Publication 2007-178758    (Patent Document 2) Japanese Unexamined Patent Publication 2006-221187